Generally, an indoor light switch is equipped with a light emitter, which forms a light spot for a user to easily locate and turn on the light switch in a dark environment. However, the light emitter only emits weak light sufficient for a user to locate the light switch, and therefore can hardly serve as a lighting fixture. An additional mini lamp is usually required for night lighting.
On the other hand, an emergency light is normally provided in a general building for lighting in an unexpected power failure. Light emitters in the emergency light are off when the public power supply is normal, and a battery of the emergency light is charged. In the event of a power failure, an internal switch of the emergency light switches on the battery for the same to supply power to the light emitters, so that the emergency light keeps lighting. However, the emergency light is usually fixedly mounted to a relatively high place in the building. Therefore, the emergency light could not be inconveniently checked or tested. Moreover, once the emergency light is mounted, it is unmovable. This limits the emergency light to illuminate only a small area from a fixed angle. Furthermore, the existing emergency light has a considerable large volume and it is often necessary to drill holes on a wall for installing the emergency light. Such procedure is quite troublesome and complicated. Therefore, people rarely install such emergency light in general family houses. Instead, a flashlight is often used as a domestic emergency lighting device in a power failure. However, while the flashlight has a small volume and is easily portable, it is frequently positioned by a user at different places and can not be quickly located for use in a sudden power failure.